The present invention relates to a vane pump, for example, a rotary pump used for various devices such as a supercharger of an engine, a compressor of a freezing cycle, etc.
A vane pump schematically shown in FIG. 4 has been heretofore widely known.
In FIG. 4, reference numeral 31 designates a housing, 32, a rotor inserted eccentrically into an inner peripheral space of the housing 31 and rotatably supported by a rotational shaft 33; 35a, 35b and 35c, plate-like vanes disposed radially retractably from vane grooves 34a, 34b and 34c equally spaced apart so as to peripherally divide the outer peripheral side of the rotor 32 into three sections. When the rotor 32 is rotated in the direction as indicated by the arrow X by the rotational shaft 33, the vanes 35a, 35b and 35c are moved out in the direction of the outside diameter by the centrifugal force, and the end edges thereof rotate while slidably contacting the inner peripheral surface of the housing 31. Since the rotor 32 is eccentric with respect to the housing 31 as previously mentioned, as such rotation occurs, volumes of working spaces 36a, 36b and 36c defined by the housing 31, the rotor 31 and the vanes 35a, 35b and 35c are repeatedly enlarged and contracted to allow a fluid taken in from the intake port 37 to be discharged out of an outlet port 38.
However, the above-described conventional vane pump has problems that since the vanes slidably move along the inner peripheral surface of the housing at high speeds, the efficiency of volume caused by the great power loss due to the sliding resistance and by the generation of high sliding heat unavoidably deteriorates; the vanes materially become worn; and the vanes are expanded due to the generation of sliding heat to produce a galling with the inner side surface of both end walls of the housing, and the like.
In view of those problems as noted above, it is an object of the present invention to enhance the efficiency of pump and enhance the durability.